Background: The internal mammary artery and vein is often used as a site of anastomoses in microvascular breast reconstruction. This area supports lymphatic drainage of the breast and its role in breast cancer metastasis remains unclear. We hypothesize that sampling of internal mammary lymph nodes at the time of microvascular anastomoses preparation may identify persistent or recurrent local disease and mandate the need for additional treatment in this area.
Material/Methods: A retrospective chart review from 519 patients in the time between January 2006 and September 2009 was performed on all patients who underwent internal mammary lymph node sampling at the time of microvascular breast reconstruction.
Results: Microvascular breast reconstruction was performed in 519 patients. Enlarged internal mammary lymph nodes were found and harvested in 195 patients for histological review. Six of 195 (3.08%) were found positive for metastatic disease requiring additional oncologic treatment.
Conclusions: The internal mammary lymphatic drainage system is an important and often underappreciated pathway for breast metastasis. Routine sampling of these lymph nodes at the time of microvascular breast reconstruction is easy to perform and is a useful tool to identify women, who might require additional treatment and increase cancer-free survival.

Keywords: Neoadjuvant Therapy, Mediastinum - pathology, Mammaplasty, Lymphatic Metastasis - pathology, Lymph Nodes - surgery, Breast Neoplasms - surgery, Sentinel Lymph Node Biopsy, Transplantation, Autologous, young adult